This interdisciplinary research program, in progress since 1958, shares a common framework in the sociopsychological study of change in adult life. Its objective is to differentiate external and intrinsic factors associated with life course change in mental and physical functioning and to trace consistencies and inconsistencies in perceptual and coping processes that prove adaptive at successive adult life stages, both within the majority and key minority cultures. A multidimensional concept of mental health is used and emphasis is given to subjective perception of circumstantial reality. The program consists of two core studies. The Longitudinal Study of Transitions examines the interrelationship of four parameters: (1) situational factors: measurable dimensions of the social structure (socioeconomic status, social roles and networks) and presumptive or actual stress; (2) perceptual characteristics: subject's appraisal of sociostructural variables and stress; (3) values, goals, and goal-motivated behavior; and (4) indicators of adaptation: morale, self-concept, psychological resources and deficits. The study focuses on the negotiation of four normative life transitions, two of which are incremental and two decremental. The cross-sequential research design consists of a four- year follow-up of an earlier baseline study and the addition of two new samples in order to assess cohort differences. The Study of Ethnic Identity and Adult Development applies a psychosocial model of identity cross-culturally and developmentally testing the thesis that such identifications have adaptive as well as maladaptive functions. A strong ethnic identity may be functional at one stage of life by providing positive role models and a broad range of acceptable behavior; at another stage it may impose limitations on individual growth.